Barclay's performance also lead to an invitation to her first stage performance, on Neil Armfield's 2009 production of Gethsemane in Sydney. Armfield later indicated Barclay to Lee Lewis, who cast her in the play That Face. In 2011, she performed in another Belvoir production, The Seagull, and acted opposite Geoffrey Rush in the Melbourne Theatre Company's The Importance of Being Earnest. In 2012, Barclay performed opposite Hollywood actors Michael Cera and Kieran Culkin in This Is Our Youth, returned to Belvoir with Strange Interlude and debuted at London's Young Vic performing on Three Sisters.